Large diameter ultra-high temperature butterfly valve for catalytic cracking unit energy flue gas recovery system, the normal operating temperature of the device 680 ℃, allowing the highest continuous use temperature of 720 ℃, the maximum over-temperature 800 ℃, the transport of catalyst particles containing renewable flue gas medium. Due to the strong erosion of the medium on the valve, in order to prevent the body wall thickness due to scouring thin failure, the body of a large area of ​​hard alloy surfacing, the valve body can easily produce deformation and cracking, surfacing difficult. Because the system temperature is high, the mechanical properties of metal materials in a sharp drop in high temperature, the valve should be used high temperature materials. In order to prevent excessive valve leakage, causing the system can not stop the normal smoke machine, resulting in major accidents, valve sealing structure and parts of the processing accuracy of the higher. Large-caliber ultra-high temperature butterfly valve body made of welded steel plate and forged flange. Stem for the overall structure of the forging, supported by the external bearing, and through the two-pin connection driven valve flap rotation. 2 semi-circular valve seat staggered back and forth, and the valve was symmetrical distribution, combined with symmetrical streamlined valve structure, so that the valve has a good flow of performance. Three sets of packing seals, plus sealant and purge two auxiliary seals to form a highly reliable stem packing seal system. Ultra-high temperature butterfly valve in order to meet the requirements of high temperature, must meet the following requirements: 1, the valve body material design standards for the ASMEB16134. According to the standard pressure - thermometer calculated at room temperature pressure grades, is the design basis, and in order to calculate the minimum wall thickness. In the design process, the valve body material is also selected ASME B16134 standard material, and the material temperature is higher than the maximum operating temperature of the valve. After consulting a large number of similar conditions at home and abroad the use of valve equipment materials, combined with the experience of the use of high temperature materials, choose a high cost 304H as the valve body material. This material reduces the effect of creep on the material. 2, the stem material According to the estimation of high temperature strength, austenitic steel at 704 ℃ under high temperature conditions, the intensity decreased by 6415%, if increased by the stem diameter to increase its strength, the valve structure requirements beyond, so Austria Steel is not suitable for body stem material. lnconel X - 750 in the high temperature conditions 704 ℃, the intensity decreased 4113%, but the intensity is still very large. According to the yield strength, and consider the durability of the calculated stem diameter, in line with the valve structure requirements, the stem material selection lnconel X - 750. 3, ultra-high temperature filler filler selection of flexible graphite. It has an oxidation temperature of 450 ° C in air and a 1% reduction in mass at this temperature every 24 hours. The higher the temperature, the more mass is reduced and the more serious the oxidation is. Flexible graphite packing maximum service temperature of 650 ℃, and only for non-oxidizing media. Taking into account the packing stuffing box in the tight seal, only part of the contact with air, there is information on the use of packing in this state can reach 816 ℃ temperature. Large-caliber ultra-high temperature butterfly valve development, mainly to solve the main body of the valve body material selection, butterfly valve seal vice structure and the design of the valve stem seal structure and selected by the test of ultra-high temperature filler for the petrochemical industry catalytic cracking unit valve Design and manufacture. Search Keyword: More Valve Technical Articles